Work Step by Step
When taking the square root of a number, you get a positive and a negative answer. $2.5(x-6.5)^2-20=42.5$ $2.5(x-6.5)^2=62.5$ $(x-6.5)^2=25$ $x-6.5=5$ $x=11.5$ or $x-6.5=-5$ $x=1.5$. So $x=1.5,11.5$.
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